Nazir 47: Who Should Become Tamei?

We end Perek V with a final Mishna: if one is partially through the ritual of purification and becomes impure, shouldn't his/her nazirut be completed?  The Mishna shares the story of Miriam of Tarmod, who left part way through her purification to be with her daughter who was mortally ill.  On arriving home, her daughter died, and so she became ritually impure via contact with a corpse.  The rabbis agree Miriam of Tarmod should be permitted to return with her remaining offerings and complete her purification.

Perek VI focuses on a more detailed comparison between the halachot of nazirites and those of priests and High Priests.   In particular, if there are situations that require that one of these two groups of people should become tamei, ritually impure, who should become impure?  A Mishna tells of a Kohen Gadol, a High Priest, and a nazirite who come across a met mitzvah, a Jewish corpse with no one available to bury it.  Which one should become tamei?

The rabbis argue that a nazirite should become tamei.  This is because the nazirite will be forbidden from becoming tamei only temporarily.  What about those for whom nazirut is perpetual?  The rabbis suggest that kohanim are born into these halachot/restrictions.  

One of the examples that the rabbis use to clarify their thinking regards a kohen who is anointed for battle and a deputy Kohen Gadol.  Both are forbidden from becoming tamei in perpetuity.  The rabbis argue that the deputy Kohen Gadol is required to be tahor, ritually pure, specifically if this function is needed because the Kohen Gadol is unable to perform his duties.  However, the anointed kohen is required for the morale, the leadership, and the ultimate success of Israel's warriors at a time of war.